Machine for making dowel-pins.



110.7%,432. I PATBNTED NOV. 22,1904. 0. F. STEWART. MACHINE FOR MAKINGDOWEL PINS.

APPLICATION FILED MAY 16, 1904.

" 3 SHEETS-SHEET 1.

PATENTED fiovjz z, 1904.

0. F. STEWART. MAGHINE FOR MAKING DOWE'L PINS.

APPLICATION FILED MAY 16, 1904.

a SHEETS-SHEET 2 N0 MODEL.

NOQ 775,432. 4 PATENTED NOV. 22, 1904. 0. F. STEWART.

MACHINE FOR MAKING DOWEL' PINS.

APPLICATION FILED MAY 16. 1904.

N0 MODEL. a sums-sum 3.

WITNESSES: INVENTOR 2km. KMCM,

qr, ATTORNEY- UNTTEE STATES Patented November 22, 1904.

PATENT OEETQE.

MACHINE FOR MAKING DOWEL-PINS.

SPECIFICATION forming part of Letters 1? Application filed May 16, 1904.

To all whom, it may concern:

Be it'known that I, CLARENCE F. STEWART, a citizen of the United States,residing at Vassar, in the county of Tuscola and State of Mich: igan,have invented certain new and useful Improvements in Machines for MakingDowel. Pins; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention is a machine for making dowel-pins, and relatesparticularly to certain features in a dowel-pin machine of the class inwhich pins are formed by forcing a rectangular block endwise through theannular die.

The objects of the present improvements are to so construct theguide-block and guide-shoe by which the rectangular blank is directedinto the die that friction between the guideblock and blank will bereduced to the minimum, and the machine will therefore require lesspower to drive it and is much easier to feed, thereby insuring a greaterper cent. of good pins.

Further objects are to provide means for reducing the pressure of theblank'against the block, this means consisting in the peculiar manner inwhich the splitting-knife is mounted, the knife being set at a slightangle from the vertical and having a tendency to draw the blank downinto the shoe, thus relieving the pressure on the guide-block while theblank is being forced through the splitting-knife. Means is alsoprovided for mounting the reciprocating plunger in its guides, so .itwill remain firmly supported centrally alined with reference to thehollow die and will be incapable of lateral movement even when theguides become worn.

Another improvement lies in the construction of the splitting-knife,whereby two interchangeable knives are formed in one piece, thisconstruction being such that two knives may be made at almost the samecost as a single knife.

I have also provided a new construction of guide-block, whereby theblock may be inverted when one side is worn, increasing the life of theblock.

thus greatly Interchangeatent No. 775,432, dated November 22, 1904.

Serial No. 208,252. (No model.)

able springs for yieldingly holding the guideblock against theguide-shoe and knife are also employed, giving uniform pressure both ontop and on the side of the guide-block. The connecting-rod is madeadjustable, whereby the stroke of the plunger relatively to thesplitting-knife may be regulated.

A further improvement lies in the construction of the annular die andthe device by which it is held in place, whereby the cost of the die isgreatly reduced.

With these objects and certain others which will appear further in thespecification my invention consists in the device illustrated in theaccompanying drawings, in which Figure 1 is a top plan view of themachine with the hollow die removed. Fig. 2 is a side view, broken awayin part, showing the hollow die in place. Fig. 3 is a rear view of themachine, the die being removed. Fig. 4 is a part-sectional detailshowing the construction of the spring-chuck for holding the hollow die.Fig. 5 is a front view, and Fig. 6 is a rear view, of the parts shown inFig. 1. Fig. 7 is a top view of the bracket that supports the die-chuck,and Fig. 8 is a rear view. ig. 9 is a perspective of the guide-shoe, theposition of the knife being shown in dotted lines. Fig. 10 is aperspective of the knife. Fig. 11 is a front perspective of the guideblock. Fig. 12 is a side perspective of the same, showing part of thepresser-spring. Fig. 13 is a detail in side elevation, showing therelative arrangement of the plunger, knife, guideblock, and guide-shoe.Fig. 14 is an end view showing the relation of the knife to theguide-block. Fig. 15 is a top plan view of the parts shown in Fig. 13.

As is shown in the drawings, the device consists in a power-operatedcrank 1, having rearwardly-extending counterbalances 1 to reducevibration and an extensible connectingrod 2, journaled at its forwardend to the reciprocating plunger 3, carried by horizontal guides 1. Asthe plunger moves back and forth its forward end 3 advances toward andrecedes from the splitting-knife 5 and the guide-block 6, which isyieldingly pressed toward the splitting knife by means of the spring 6'.

As is well known, in this class of machines wooden blanks having thegrain extending lengthwise the machine are fed in front of the plunger 3and pushed forward against the splitting edge of the knife, therebysplitting from the blank a rectangular strip, which is forced through anannular die, and thereby converted into a dowel-pin at the next strokeof the machine. It is found in practice that machines of this typerequire considerable pressure on the top and side of the guideblock, andI have devised a guide-block and guide-shoe construction that eliminatesa large part of the resistance. This guide-block construction is shownin Fig. 11, where 6 is a longitudinal groove formed in the inner cornerof the rabbet that extends along the lower corner of the front side ofthe guide-block. This groove forms a clearance for the corner of theblank and insures that the only rubbing contact will be that of thefaces of the rabbet against the faces of the blank.

In order to keep the reciprocating plunger 3 central in its guides, Ihave adopted the construction shown in Figs. 13 and 14. The plunger isformed from a rectangular bar with its diagonal vertical, and thus thebar rests in the V-shaped groove of the guide 4. When the groove wears,the bar by its shape is prevented from shifting laterally, and thereforeremains always in the vertical plane of the axis of the hollow die.

By referring to Fig. 14 it will be seen that the splitting-knife 5 isnot vertical, but is tilted slightly toward the guide-block. This slighttilting of the knife results in a tendency of the blank to draw closeinto the corner formed by the knife 5 and the guide-shoe or table 7, andthereby makes unnecessary the heavy pressure which would be required tobe exerted by the yieldingly-pressed guideblock 6 if a vertical knifewere used. In prac tice I prefer to form the splitting-knife as shown inFig. 10, where 5 and 5 are cuttingblades formed in the diagonallyopposite edges of a steel plate 5. This plate may be mounted in anysuitable manner so that the blades 5 and 5 by invertingthe plate may beused interchangeably.

To hold the guide-block 6 in place, I employ a pair of interchangeablecoil-springs 8 and 9, mounted in any suitable yoke or bracket 10 in sucha manner as to exert yielding pressure against the top and side of theguideblock 6, respectively. The advantage in making the springsinterchangeable is that the same amount of pressure will always beexerted upon the side of the blank as it passes through the knife aswill be exerted upon the top and the necessity of employing two sizes ofsprings is avoided.

To compensate for any slight lengthening or shortening of the travel ofthe reciprocating plunger due to wear in the journals or receding of thecutting edge 5 of the knife by wear, I provide the adjustableconnectingrod 2. This rod is constructed by providing threaded recesses2 in the journals at its ends and forming right and left hand threads onthe respective ends of the rod to engage the journals. Set-nuts 2 arethreaded on the rod to preserve its adjustment.

Tapered annular dies heretofore used to form the pins are expensive, andto produce a simple die that can be more cheaply manufactured and toprovide suitable means to rigidly clamp it in position I provide thedevice illustrated in Figs. 4, 5, and 6, in which 11 is an annular dieof the usual form, except that its outer surface 12 is cylindricalinstead of tapered. I clamp this die 11 rigidly in a chuck 13, which canbe held in the bracket 14 by any suitable means. The chuck is in theform of a hollow spindle having a recess 13 to receive the die 12, saidrecess being formed with a shoulder 13 to receive the thrust of the die.The forward end of the chuck 13 is tapered slightly and threaded, as at13, to receive the internally tapered and threaded nut 15. Radial slits13 are. formed in the threaded end of the chuck, as shown in Fig. 5.When the nut 15 is screwed up, the slitted ends of the chuck 13 aredrawn together, so as to firmly grip the die 12 and hold it in properalinement.

By the means above described I have produced a dowel-pin machine that issimple in construction, requires small power to drive, and is not liableto get out of order.

What I claim as my invention, and desire to secure by Letters Patent, isas follows:

1. In a machine of the class described the combination with thereciprocating plunger and the annular die, of a rabbeted guide-blockhaving a clearance-groove formed in the corner of the rabbet, for thepurposes set forth.

2. In a machine of the class described, the combination with thereciprocating plunger, the counterbalance-crank, and the extensibleconnecting-rod; of a spring-pressed rabbeted guide-block havingaclearance-groove formed in the corner of the rabbet, together with atilted splitting-knife, and a cylindrical annular die, substantially asdescribed.

3. In a machine of the class described, the combination with thereciprocating plunger, the springpressed guide block and fixedguide-shoe; of a splitting-knife arranged opposite said guide-block, thetop of said knife being inclined toward the guide-block, for thepurposes set forth.

In testimony whereof Ia-ffix my signature in presence of two witnesses.

CLARENCE F. STEWART.

Witnesses:

W. I. (JA'rHcART, A. A. EASTERLY.

